'97 US Passat (B4) rough running for first 30 seconds

hamilgs

Veteran Member
Joined
Sep 1, 1999
Location
Huntsville, AL USA
TDI
2004 Jetta & 2014 JSW 6MT
\'97 US Passat (B4) rough running for first 30 seconds

Our '97 US spec Passat TDI (96K miles) is starting fine, but recently stumbling and belching grey smoke for about the first 30 seconds. From the driver's seat, you can feel the engine bucking and kicking, tranny in neutral. Smooths out after 30 seconds or so. My favorite 16 year old is the prime driver, and she's been complaining of poor fuel mileage. How poor I ask her, and she does not know-won't reset trip odo at each fill up, and write down results. What I have done already: Recent fuel filter, air filter, cleaned snow screen in airbox (half clogged), checked upstream (airbox) screen on air flow meter. Temperatures outside (car not garaged) are moderate; 55F-80F, so I don't think glow plugs are at fault. No check engine light. Have wondered about an injector having poor spray pattern, and -heaven forbid-low compression on one cylinder.--george
 

jck66

Top Post Dawg
Joined
Jan 4, 2001
Location
Greenwich, CT, USA
TDI
12 Passat SE / 14 BMW 535d
Re: \'97 US Passat (B4) rough running for first 30 seconds

I would have guessed glow plugs. This sounds like exactly the way my old 1.6 IDI cars used to act if I forgot to pull out the "handle". Sorry I can't help more.


Would it be possible for you to restrict your daughter's driving if she doesn't at least keep a log of her fillups? 16 years old is a perfect time to instill good car habits.
 

GMCpatrick

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Joined
Aug 16, 2001
Location
Atlanta
Re: \'97 US Passat (B4) rough running for first 30 seconds

I recently experienced the same thing, with the same concern over the possibility of low compression in one cylinder. This past weekend I cleaned my intake manifold and disconnected the EGR. Along with tremendously improved performance, the cold start problem has gone away.

At 96k miles I'd wager that, if the EGR system is intact, then you've likely got a clogged intake manifold.

Patrick

[ October 15, 2002, 06:19: Message edited by: GMCpatrick ]
 

mavapa

Veteran Member
Joined
Aug 29, 2000
Location
rome, ga
TDI
2001 golf
Re: \'97 US Passat (B4) rough running for first 30 seconds

I don't understand why a clogged intake would cause a start problem that goes away after 30 seconds. Could there be a small leak in a fuel line that lets some air into the line while it sits without releasing a significant amount of fuel?
 

SoTxBill

Top Post Dawg
Joined
Dec 14, 2000
Location
its not the base, its the additives!!
TDI
13 passatdsg 10 jetdsg, 09 jetdsg, 2006 jetdsg, 2001Jet, 96passat, 86jet, 81 jet, 78pickup all vw diesel.
Re: \'97 US Passat (B4) rough running for first 30 seconds

bad glow plug... for the starting problem

as to bad mpg
then check for dirty injectors.. a can of BG 44k will fix that..if they are only dirty..

check air filter, and engine timing, and tell her not to sit and idle why she talks for another 20 minutes to her friends... gosh,, that was a great age... back when the indians chased me to school..

good luck...
 

GMCpatrick

Veteran Member
Joined
Aug 16, 2001
Location
Atlanta
Re: \'97 US Passat (B4) rough running for first 30 seconds

Originally posted by mavapa:
I don't understand why a clogged intake would cause a start problem that goes away after 30 seconds.
<font size="2" face="Verdana, Helvetica, sans-serif">Maybe because the engine is starved for air. It sure cleared up the same problem on mine. Easy to check - pull your intake inlet hose off and shine a flashlight into the opening. If the intake is blocked, you'll be able to see it. BTW, don't be tempted to scrape any of it out with the intake on the engine - anything that comes loose can fall right down the intake runners.

Patrick
 

Metalnerd

Vendor , w/Business number
Joined
Nov 14, 2000
Location
Greensburg, PA, USA
TDI
96 Passat TDI Storm Grey
Re: \'97 US Passat (B4) rough running for first 30 seconds

Grey Smoke: Bad Glow plug, leaky injector

In my 125,000 mile experience on the 96 Passat:

Huge Impact: Short trips on cold engine <5 miles each
Second: Winter Temps/winter fuel
3rd: Tire Pressure
distant 4rd: Driving habits & speed
Mostly local driving typically produces ~43
Mostly highway driving ~47
Pure Highway Driving ~50

Large special cause: Rear Brake Drag


[ October 18, 2002, 10:05: Message edited by: Metalnerd ]
 
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